Indurated porous material and process of forming same



O; C WINESTOGK.

[NDURATED POROUS MATERIAL AND PROCESS QF FORMING SAME. APPLICATION FILED uens. I919.

Patented May 10, 1921.

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UNITED STATES P ATENT OFFICEQ 1 OTTO c. wrnnsrroox, or PERKINSVILLE, VERMONT, Assionon 'ro WALTER w. sLAcK,

or SPRINGFIELD, vnruvron'r.

INDUR'ATED ronous mmmmm rnoonss or FORMING smi Specification of Letters Patent. baite f d M 120 2 Application filed August is, 1919. Serial No. 318,051.

Z '0 all whom it may concern:

a citizen of the United States, residing at Perkinsville, in the county of Windsor, State of Vermont, have invented certain new and useful Improvements in Induratedi Porous Materials and Processes of Forming Same, of which thefollowing is a specification.

Among its several objects and advantages,

the invention includes the provision of a new and advantageous process of indurating fibrous material whereby occluded liquids. I I I g surface preservatlon is concerned. The inand gases, such as water, wood sap, air, carbon dioxid, etc., maybe removed from the porosities of fibrous materials such as wood,

and the porosities permanently filled with a tenacious elastic material, so as to effectively eliminate the capillary, bibulous and hydroscopic qualities of the wood, increase ts homogeneity and density, and preserve its structural form.

Another object of the invention is the provision of a novel method ofthe' sort specified which is effective in securing the intended results in a very short period of time.

Another object of the invention is the provision of a process having the attributes above mentioned and which may be effectively practised upon articles of consider-' able size or bulk, such as blocks of wood having such mass or thickness as'not to be ordinarily penetrable liquid.

A further object of the invention "is the" provision of a process having the attributes above specified and'whichmay be practised at very low costand with entire safety to the materials upon which it is used, the

plant in which it is utilized, and the -indi-.

viduals by whom it is actually carried on.

an article of manufacture consisting of a shoe last formedof wood, having its porosities filled with a stable tenacious elastic material and possessing certain distinctive This invention relates broadly to theindurating of fibrous materials, and speclfically seasoning process. or permeable by A still further object of'the invention is p advantages and novel features hereinafter Be it known that I, O'r'rojC. WINESTOOK,

to be more particularly pointed out.

Other objects of the invention will be obvious from the following specification and claims, and the drawings forming a part of the specification or will be pointed out'specifically therein Heretofore the induration of fibrous materials such as wood, leatheigand the like, 7

have been successful only within limits quite strictly imposed by the size of the porous wooden articles, such as blocks or piling, of spruce or pine, with creosote preparations has been developed to a fairly satisfactory commercial degree so far as the ,factthat those skilled in the art have been unable to secure a sufficient penetration of the material by the indurating fluid by any commercially practical method. Various expedients "have been resorted to :to increase the extent of penetration oh" permeation. One condition heretofore regarded asprerequisitehas been that'the Wood be' thoroughly dried and seasoned before being subjectedto the indurating process.

Thepredrying or seasoning requires several months of careful handlingin dry houses, and is attendedwith a considerable, loss of materialffrom checking and cracking in the Accordingly it is extremelyexpensive. Efforts have been made to increase the penetration of'the indurating fluid .by the use of pressure. I This has proven unsatisfactory, both from the danger andcost incident toutilizing pressure, and

due also to the factthat as the pressure 1n-' fluence 'is'but temporary, indurating fluid forced intothe porosities of the wood under pressure is subsequently expelled with. greater or less rapidity by the expansion of the occluded gases withinthe wood, when the exterior pressure-is removed, or the'generation of further pressurein the wood by the decomposition oforganic matter therein.

Certain experimenters have endeavored to secure increased penetration by forming artificial channels into the wood for the passage of the indurating fluid by punching or boring holes, or by forcing apart the wood fibers. The treatment of the material in this fashion is necessarily objectionable when it is intended for uses which require 'homogeneity of the structure, and particularly a smooth, well finisl ed and resistant surface.

By the employment of the process comprised in my present invention, I am enabled to eliminate the disadvantages pertaining to the methods heretofore employed, and also to secure certain distinct advantages not contemplated by others who have been active in the art. For example, I am enabled to take blocks freshly cut from green logs and, by my process, completely expel the gases and liquids occluded in the pores of the material, and fill all such porosities with a stable elastic material which will prevent reabsorption of gases or liquids by the wood, all in the course of a single treatment within a very short time.

While'my process is suitable for use upon a great variety of articles I will describe it as applied to the indurating of wooden blocks for the manufacture of shoe lasts, and the drawing shows an article of that kind for the purpose of illustrating the process.

In the drawing, Figure 1 represents a side elevation of a last block Fig. 2 a section on the line 22 of Fig. 1 and Fig. 3 a diagrammatic illustration of an apparatus for practising the process.

As is well known in the art, in the manufacture ofshoes, lasts made of wood are employed upon which the shoes are shaped and built. hese articles must possess certain characteristics in order to fit them for their use. In the first place, the material must be suitably workable so that the last may be accurately formed to the proper size and shape. Furthermore, thematerial must be of such quality as to have a minimum susceptibility to weather or atmospheric changes, in order that they may retain their shape and their size accurately. In present practice it is customary to keep the lasts, when not in use, in a dry-house wherein the temperature and moisture content of the air are carefully regulated for uniformity.-

or gather foreign matter, and in order that they may be manipulated easily in removal from the shoe. They must be firm and of good density because of the handling to which they are subjected in the manufacture of the shoes so that they will hold the last ing tacks but will not be made soft or porous or pulpy by the punctures thereof. The life of a last is limited both by the usage to which it is subjected and by change in styles of foot wear. The average last is good for use in about eighty shoes. Due to the necessity of replacement, there is an annual requirement of something in excess of three million blocks for this use. The present customary practice is to cut the blocks, intended for manufacture into shoe lasts, from hard close grained and homogeneous timber such as hard maple, and then subject the blocks to a course of drying and seasoning extending over a period of several months.

In the manufacture of indurated blocks suitable for shoe lasts by the use of my improved process, I take the blocks of wood, just either dried or as they are cut from the logs, and while yet unseasoned and having vided with a venting channel 2. This ventl ing channel is preferably formed by boring a hole in the material so as to leave a clear and unobstructed channel, said hole being formed in a portion of the block where it will not interfere with the use of the finished article. It is important that this venting channel extend deeply into the block, and it is desirable that it'penetrate the block in its most massive portion. Preferably the channel is bored transversely of the grain of the wood so that it will intersect as many as possible of the natural'veins, channels and rays of the wood structure. It. is not neces sary, howeveigthat the venting channel be formed across the grain, as it is effective also when formed parallel with the grain. In the illustration I have shown the venting channel .as extending deeply into the last 'block at the thickest part thereof, which is in a portion corresponding to the arch and instep of the foot, and in which location it will not interfere with any of the uses to which the last is put. The channel may be formed in other locations, however. So

prepared, the green blocks are ready for subjection to'the processing with the indu I v l of the indurating liquid. This actionjis evidencedby the fact that during the treatrating compound.

The indurating compound comprises'*a substantially saturated solution of vulcanized rubber inordinarykerosene. Thefape proximate proportion is l pound of rubber to 6 quartsof kerosene, but the exact'pro portion depends .upon the quality of rubber used. If itfis comparatively new .and',1ive

rubber, a jsmallerproportiQn will give the composition the proper body than if'the rubber is old rubber. The rubbe'riutilized may be in the form of scrap rubber such as old vehicle tires, "inner tubes and thei like.

The solution is obtained by raising the kero sene to a temperature sufficiently high to melt the rubber, and then mixing in the" rubber in small pieces until the liquid has taken up all that itcan hold. Any solids and foreign matterflcontain'edfin the rubber scrap will be precipitatedor floated and are,

readily strainedout of the liquid, 1eaving the latter clean and free, from slime. In some cases it may be desirable to'a'dd a very: small amount ofamyl acetate, which contriba utes somewhat to hastening I the dissolution of the rubber, and-also todisguisinglany disagreeable odor of the compound.

The indurating. compound 2 having been thus prepared, itis placed ina suitable ves-f sel or kettle l and the blockspprepar'edas above described, ldeposited'in it, preferably while it is cold. The liquid with theblocks is then raised to a'temperat'ure of from 140 F. to 198 F. and maintained'thereat for a period suitable to permit thepermeation of the material of the blocks by the indurating liquid. In the case of wetg'reen blocks ofhard maple wei hing in the neighborhood of 30 ounces and 7 described, I havefou'nd thatthe treatment With the liquor at the] temperature above mentioned. for about twenty-four hourshas been effective. During the treatment of the} blocks in the liquid, it appears that fol lowing takes place: e Y v The heat transmitted to the wood through the liquor is effective to expand the same somewhat and increases its bibulous capac ity, thereby facilitating the rapid penetra-i tion of the liquid into the porosities of the wood. This penetration is contributed-to, no doubt, also by the hydrostatic pressure of the liquor upon theouter' surface of the blocks. The penetration of the hot liquor, into the porosities of the wood conveys the heat to the occluded gases and entrained liquids therein, causing an expansion of the former, which is effective to force theliquids out of the channels in which they are entrained. Their evacuation is accommo dated by the vent which provides a channel of egress from the interior of the block,'so

suitably vented as above that there is noiopportunity given -for -de-' "velopment of a pressure Withinthe porosi--' ties of the Wood effective to resist the ingress j "liquids, and other gases generated in the porosities of thewood by the heat. Part of the water. thus expelled from the wood passes off as vapor, and part of it settles to the bottomv of the receptacle, being immis cible with the indurating fluid. This dis charge from "the venting channel gradually decreases in volume during the'period that the blocks are left inthe liquor. When the discharge ceases to ,be perceptible, it may be taken as indicative "ofth e fact that the orig-f inally occluded and entrained. gases and liquids havebeenf displaced-by the indurat ing fluid. S uch acondition in the block s having been reached, the source of heat to I the vessel is cut o'fl sothatthe liquor *and' the blocks therein will befallowed to cool gradually. These blocksare left in the liquid' for a suflicient time to permit them reaching approximately atmospheric temperature,and;even longer if they are dense. With blocks, of the sort above described, I

ing liquid and permitted to dry in the at:

mosphere. This they do quite rapidly, all

have foundthatthree days-111' the liquid after the heating have given excellent results.

excess liquid on the surface being evapo- I rated, leaving the material dry and clean. The kerosene in the liquid which haslpenetrated the wood gradually evaporates, leaving' the porosities'filled with the rubber.

Blocksin this condition may then be shaped and dressed down to the form of the finished lasts, without further treatment or seasoning V f y If desired, the lasts may be re-treated after being finished, the course of procedure above described being repeated. This will con-j tributeto the production ofv the hard smooth finished surface on the finished last.

,Asa' 'means of heightening the finish, and producing a polish and'case-finish, in the treatment of finished lasts there may be added to thefliquid an amount of :pure linseed oil equaling about of the total vol;- i

ume. The 'linseedoil is added to the rubber-kerosene composition just after the lat-' ter has been made and clarified, and while it is still hot This small quantity of linseed oil oxidizes on the surface finish on the lasts,

lheightening the finish and producing a very I lhave specified abovethat a temperature of about 198 F. is effective in the treatment of the blocks. This, of course, admits of variation. The point to be observed is that as high a temperature as possible is desirable, excepting that the temperature must not be permittedto reach the point where it will cause expansion of the occluded gases and liquids greatly in excess of their rate of egress, as such development of pressure Within the wood structure forces the fibers apart and produces checking. Blocks subjected to this process and indurated by the composition specified show no eflects from subsequent atmospheric changes or wettings or dryings, even under extreme conditions which would not be encountered in practical This may be explained use of shoe lasts. from the fact. that the occluded and entrained gases and liquids are displaced, and from the particular nature of the indurating material. In the indurating fluid the kerosene constitutes a solvent and. vehicle in which the rubber is handled for-transmission into the porosities of the wood. Kerosene forms an excellent vehicle in this-composition and process due to the facts that it forms an effective solvent and carrier for the rubber and, while sufficiently volatile to evaporate under atmospheric temperatures leaving the rubber in situ, it is not so volatile as to be dangerous in the practice of the process with the use of an open flame for heating the containing receptacle. For this reason also there is no expensive loss by evaporation of the liquid under the increased wood under the influence of the heat, be comesoccluded therein upon the cooling of.

the blocks and forms a tenacious elastic filler completely occupying. and closing such porosities, coating the cell structures and thereby insulating them and inhibiting changes intheir hygroscopic condition. The rubber, being tenacious and coherent, forms a highly stable filler, so that it is not displaced by changes of temperature, and its composition is not broken down. Hence, it does not exude from the wood. Being elastic, andbeing deposited in the porosities of the wood when the latter are expanded by heat, it accommodates the expansion and contraction of the wood structure without being itself displaced, andvvithout permitting the porosities to become open or unoccupied. In these particulars it differs quite essentially from various indurating compositionswhich include grease or other unstable constituents. In the use of prior compositions of this kind I have observed that the material, under different influences, breaks down, so that Various of its contents, such as the greases, are exuded from the surface of the wood. Not only does this render the surface sticky and place the article temporarily outofuse, but it also indicates the progressive loss of the filler. Inasmuch as it is the filler which is depended upon to inhibit the susceptibility of the wood to mois ture and atmospheric changes, it will be seen that the loss of the filler means the'reduction ofv the ability of the material to maintain its size and form in the presence of different moisture and atmospheric conditions. My indurating composition, especially when ap plied by the process described, has the further advantage, particularly in contrast to compositions which include non-volatile greases, of providing a binder for the cellular structureof the wood which is effective to preserve its structural form and increase its density andhomogeneity. Compositions heretofore employed and containing greases have the effect of softening the wood structure, rendering the cellularand fibular structure more loose and pliable, and thereby making the article soft and, to a degree, pulpyfIt will be seen, therefore, that anarticle indurated with my improved composition will be distinctly superior to those treated with the prior compositions in any uses wherein hardness and homogeneity of the structure and smoothness and durability of surface are important. For this reason shoe lasts having a structure characterized by. the inclusion of my improved indurating composition are of distinct superiority. Not only are they immune to the contemplated moisture and atmospheric changes, but they are also very durable and wearresisting, susceptible of hard and high finish, capable of being easily and accurately worked and formed, and are thoroughlystable inthe retention of the indurating material.

Having thus described my invention, what I claim is: v

1. The process of lnduratlng porous material which comprisesproviding the material with an unobstructed venting channel extending into the interior thereof, then treating thematerial in a bath of hot indurating liquid containing oxidizable material and permitting the egress of occluded fluid from the porosities of the material through the venting channel, permitting the material I to partially 'coolin the indurating fluid, and then subjecting the material to oxidizing influences.

2. The process 'of indurating porous material which comprises providing the material with an unobstructed venting channel extending into the interior thereof, then placing the material in a bath of hot indurating liquid containing rubber and an oxidizable material, and permitting the egress of occluded fluid from the porosities of. the material to become cool in the indurating fluid,

and then removing the material from the in durating fluid and exposing it to atmos-' phere.

' vegetable gum;

6. As an artlcle of manufacture, a shoe last comprised of wood with the porosities thereof filled with a stable tenacious elastic inlaterial and having an oxidized surface m. s p I OTTO C. WINESTOCK. 

